Link between hypertension and vitamin D deficiency

A new genetic study led by University of South
Australia epidemiologist Professor Elina Hyppönen has
confirmed a causal link between high blood pressure
(hypertension) and deficiencies in vitamin D.

The findings
just published in the Lancet Diabetes and Endocrinology
journal, drew on a sample of more than 146,000 records to
assess the association.

“We set up a Mendelian
randomisation study using genetic data from the D-CarDia
collaboration involving more than 140,000 individuals of
European ancestry from across Europe and North America,”
Prof Hyppönen says.

“We used two common genetic
variants that affect circulating 25-hydroxyvitamin D
concentrations, which are generally used to determine a
person’s vitamin D status, to measure the causal effect
between vitamin D status and blood pressure and hypertension
risk.

“And what we found was that for each 10 per
cent increase in 25-hydroxyvitamin D concentration there
were drops in both diastolic and systolic blood pressure.

“Statistically the association translated to just
over an eight percent decrease in the odds of developing
hypertension.”

Prof Hyppönen says that while
there have been some small scale studies and randomised
trials, until now, a direct causal link between vitamin D
and a lowering of blood pressure has not been shown.

“These findings may have important implications to
individuals who are vitamin D deficient,” Prof Hyppönen
believes. “The potential to prevent and reduce high blood
pressure with vitamin D in place of more expensive
medications is certainly something researchers can now
usefully explore in greater depth.”

According to
Prof Hyppönen while Mendelian randomisation helps to
determine cause and effect by using genetic data and
avoiding bias, there is always a possibility that the
findings could occur by chance.

“What will be
really important is an independent replication of this
study,” Prof Hyppönen says.

“And to advance the
work further, we need to do more research using randomised
controlled studies to look at and confirm causality and
importantly assess the clinical benefits of vitamin D
supplements and dosage levels.”

This significant
research into the relationship between vitamin D and
hypertension was funded by the British Heart Foundation, UK
Medical Research Council, and Academy of Finland.

Prof Hyppönen is a member of UniSA’s School of
Population Health working at the South Australian Health and
Medical Research
Institute.

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